In a communication network, such as an Internet Protocol (IP) network, each node and subnet has limitations on the amount of data which can be effectively transported at any given time. In a wired network, the limitations are often a function of equipment capability. For example, a Gigabit Ethernet link can transport no more than 1 billion bits of traffic per second. In a wireless network the capacity is limited by the channel bandwidth, the transmission technology, and the communication protocols used. A wireless network is further constrained by the amount of spectrum allocated to a service area and the quality of the signal between the sending and receiving systems. Because the impact of these limiting aspects can be dynamic, the capacity of a wireless system may vary over time and the system therefore can be thought of as constrained by these varying limitations. Changing levels of congestion over time is often a key cause of the time varying capacity characteristics.
In capacity constrained, multiple-access communication system, two goals are omnipresent: the successful transfer of information at the rate necessary to achieve quality goals, and the minimization of the impact of such transmissions on the ability of the system to adequately service other transfers, which impact may result in delays or disruptions. Often these goals are in conflict with each other, and are complicated by changing conditions such as congestions. Thus addressing the need to service competing concerns represents an opportunity for system optimization.
Problems can arise in attempting to attain the goal of efficient transfer on a per user basis, while simultaneously attempting to ensure that efforts to service one user do not compromise efforts to similarly serve other system users. A reduction in the quality of the user experience for one user can result when efforts to provide service to another user are imbalanced or are complicated by factors such as congestion. Accordingly, success in transferring information may be judged by how the user experiences the transfer. That is, the quality of the user experience can be a metric for judging successful transfer of information. A communication system can generally improve the user experience by avoiding disruptions or delays in the services provided to the user. Along with the time varying changes in the capacity of network, the communication characteristics that provide a positive user experience may also vary with the type of application associated with the information transfer and the level of congestion in the network. For example, for an email application, delay in delivering part of a message to the user due to congestion is preferred to failing to deliver part of the message. For video delivering modified video may be preferable to delaying delivery of all or a portion of the video, interrupting delivery of the video, or the like because of congestion or other changes to capacity or channel related characteristics
As video delivery represents a large use of bandwidth in a communications system, and as video often has greater quality expectations on the part of the user than voice data, email data, or the like, there is a need for improved solutions for addressing congestion and determining a response to mitigate the congestion while maintaining or optimizing the quality of experience of the applications running in the communications system, including those that generate and transfer video data.